
Re: Subscript on plus expression
Posted:
Nov 19, 2012 5:05 PM


Nasser ,
I'm using these as tensor indices.
Although Bob Hanlon offered a workaround (thanks Bob) Format[Subscript[arg_Plus, k_]] := Subscript["(" <> StringJoin @@ Riffle[ToString /@ (List @@ arg), " + "] <> ")", k] Subscript[a + b + 2, k],
I think the folks at Mathematica should fix this and insert the parentheses. The output of Subscript[Plus[a,b],k] should not be represented as Plus[a,Subscript[b,k]]!
 Dave
Original Message From: Nasser M. Abbasi Sent: Sunday, November 18, 2012 2:13 PM Subject: Re: Subscript on plus expression
On 11/18/2012 3:03 AM, Dave Snead wrote: > Hi, > > Mathematica fails to parenthesize the a+b in > Subscript[Plus[a,b],k] > > so the output looks identical to > Plus[a,Subscript[b,k]] > > Is this a bug? > Is there an option to force the parentheses? > > Thanks in advance, > Dave Snead > > >
Actually, just typing
(a+b) k
and then hitting ENTER will result in
a+b k
i.e. the () are gone. Same effect you showed.
It might be because subscript are meant to be applied to an atomic symbol and not combined expression like a+b. I do not know. I am not even sure what (a+b)_k is supposed to mean, math wise. Is this meant to be on the code or in a text cell? If it is in the code itself, how will it be used?
Nasser

